1 files changed, 16 insertions, 6 deletions

diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 2cb278a2f658..a9dbb27ca887 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -109,7 +109,7 @@ int pgd_huge(pgd_t pgd)
 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 {
         /* Only called for hugetlbfs pages, hence can ignore THP */
-        return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
+        return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
 }
 
 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
@@ -682,28 +682,35 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
         } while (addr = next, addr != end);
 }
 
+/*
+ * We are holding mmap_sem, so a parallel huge page collapse cannot run.
+ * To prevent hugepage split, disable irq.
+ */
 struct page *
 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 {
         pte_t *ptep;
         struct page *page;
         unsigned shift;
-        unsigned long mask;
+        unsigned long mask, flags;
         /*
          * Transparent hugepages are handled by generic code. We can skip them
          * here.
          */
+        local_irq_save(flags);
         ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
 
         /* Verify it is a huge page else bail. */
-        if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep))
+        if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep)) {
+                local_irq_restore(flags);
                 return ERR_PTR(-EINVAL);
-
+        }
         mask = (1UL << shift) - 1;
         page = pte_page(*ptep);
         if (page)
                 page += (address & mask) / PAGE_SIZE;
 
+        local_irq_restore(flags);
         return page;
 }
 
@@ -950,9 +957,12 @@ void flush_dcache_icache_hugepage(struct page *page)
  *
  * So long as we atomically load page table pointers we are safe against teardown,
  * we can follow the address down to the the page and take a ref on it.
+ * This function need to be called with interrupts disabled. We use this variant
+ * when we have MSR[EE] = 0 but the paca->soft_enabled = 1
  */
 
-pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
+pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
+                                   unsigned *shift)
 {
         pgd_t pgd, *pgdp;
         pud_t pud, *pudp;
@@ -1031,7 +1041,7 @@ out:
                 *shift = pdshift;
         return ret_pte;
 }
-EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
+EXPORT_SYMBOL_GPL(__find_linux_pte_or_hugepte);
 
 int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
                 unsigned long end, int write, struct page **pages, int *nr)